It seems like all the FUD in the article is copy-pasted from Sentry's own docs, though, no? And assuming Sentry's SDKs are open source and licensed appropriately (which seems to be the case), there's no issue (legal or moral) with directing users to use the Sentry SDK to communicate with a different, compatible product.

OP built a product because they were frustrated by Sentry's seeming hostility toward self-hosting. It doesn't feel like OP decided to build a competing product and then thought it would be a good marketing strategy to falsely push the idea that Sentry is difficult to self-host.

FWIW I've never self-hosted Sentry, but poking around at their docs around it turns me off to the idea. (I do need a Sentry-like thing for a new project I'm building right now, but I doubt I'll be using Sentry itself for it.) Even if it's possible to run with significantly less than 16GB (like 1GB or so), just listing the requirements that way suggests to me that running in a bare-bones, low-memory configuration isn't well tested. Maybe it's all fine! But I don't feel confident about it, and that's all that matters, really.